The shells of marine snails known as pteropods living in the seas around Antarctica are being dissolved by ocean acidification according to a new study published this week in the journal Nature Geoscience. These tiny animals are a valuable food source for fish and birds and play an important role in the oceanic carbon cycle*.
During a science cruise in 2008, researchers from British Antarctic Survey (BAS) and the University of East Anglia (UEA), in collaboration with colleagues from the US Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration (NOAA), discovered severe dissolution of the shells of living pteropods in Southern Ocean waters.
The team examined an area of upwelling, where winds cause cold water to be pushed upwards from the deep to the surface of the ocean. Upwelled water is usually more corrosive to a particular type of calcium carbonate (aragonite) that pteropods use to build their shells. The team found that as a result of the additional influence of ocean acidification, this corrosive water severely dissolved the shells of pteropods.
Ocean acidification is caused by the uptake of carbon dioxide from the atmosphere emitted as a result of fossil fuel burning. A number of laboratory experiments have demonstrated the potential effect of ocean acidification on marine organisms. However, to date, there has been little evidence of such impacts occurring to live specimens in their natural environment. The finding supports predictions that the impact of ocean acidification on marine ecosystems and food webs may be significant.
Lead author, Dr Nina Bednarek, formerly of BAS and UEA, and now of the National Oceanic and Atmospheric Administration (NOAA) says:
"We know that the seawater becomes more corrosive to aragonite shells below a certain depth called the 'saturation horizon' which occurs at around 1000m depth. However, at one of our sampling s
|Contact: Audrey Stevens|
British Antarctic Survey